Reliability Framework for SRv6 Service Function Chaining

Segment routing (SR) [RFC8402] is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. SR can be instantiated on the MPLS data plane (MPLS-SR) and the IPv6 data plane (SRv6). On the MPLS-SR data plane, a segment is encoded as an MPLS label, and an ordered list of segments is encoded as a stack of labels. On the SRv6 data plane, a segment is encoded as an IPv6 address (SRv6 SID) [RFC8986], and an ordered list of segments is encoded as an ordered list of SRv6 SIDs in the SR header (SRH) [RFC8754]. The ingress node steers packets into a specific path according to the ordered list of segments (SR Policy) as defined in [RFC9256]. Service Function Chaining (SFC) defines an ordered set of service functions and subsequent "steering" of traffic through them. The architecture of SFC is defined in [RFC7665]. This document describes the common failure scenarios and protection mechanisms of service function chains in SR networks. Then implementation recommendations for protection of service function chains are proposed.